U.S. patent application number 14/823327 was filed with the patent office on 2015-12-10 for retractable wheel base.
The applicant listed for this patent is United Metal Fabricators, Inc., d.b.a. UMF Medical. Invention is credited to Nathaniel Francis Barbera, Eric Richard Colburn, Scott G Ferreri, Joseph Romano.
Application Number | 20150351986 14/823327 |
Document ID | / |
Family ID | 54063388 |
Filed Date | 2015-12-10 |
United States Patent
Application |
20150351986 |
Kind Code |
A1 |
Ferreri; Scott G ; et
al. |
December 10, 2015 |
Retractable Wheel Base
Abstract
A base with retractable wheels is provided for an examination,
procedure or surgical table or chair for use in the medical,
dental, or veterinary fields that can be easily switched between a
stationary state and a mobile state. The base includes fixed wheels
on one end and on the other end stationary foot pads and
retractable wheels that can be engaged by a lift mechanism that can
transfer the weight of the table or chair from the foot pads onto
the wheels, allowing the table or chair to be more easily moved
within a room.
Inventors: |
Ferreri; Scott G;
(Duncansville, PA) ; Romano; Joseph; (Johnstown,
PA) ; Barbera; Nathaniel Francis; (Somerset, PA)
; Colburn; Eric Richard; (Wexford, PA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
United Metal Fabricators, Inc., d.b.a. UMF Medical |
Johnstown |
PA |
US |
|
|
Family ID: |
54063388 |
Appl. No.: |
14/823327 |
Filed: |
August 11, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
14298209 |
Jun 6, 2014 |
9132053 |
|
|
14823327 |
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Current U.S.
Class: |
280/43.17 |
Current CPC
Class: |
A61G 15/002 20130101;
A61G 13/105 20130101; A61G 13/104 20130101 |
International
Class: |
A61G 13/10 20060101
A61G013/10 |
Claims
1. A retractable wheel base for a patient support, comprising: a
base with a column attached to a top side of the base, wherein a
patient support is attached to the column and the column is
extendable for adjusting the patient support upwards and downwards;
a plurality of non-retractable wheels attached near a front side of
the base; and a plurality of retractable wheels attached near a
rear side of the base, wherein when the retractable wheels are
retracted the base rests on leveling feet near the rear side of the
base and on the non-retractable wheels near the front side of the
base and when the retractable wheels are engaged the base rests on
the retractable wheels on the rear side of the base with a lower
portion of the retractable wheels being not more than approximately
one-half inch below a bottom surface of the base and on the
non-retractable wheels on the front side such that the base can be
repositioned when on relatively flat surfaces.
2. A bottom support for a medical table or chair, comprising: a
base plate having a first end and a second end; a column attached
to the base plate with a seat base assembly attached to the column,
wherein the seat base assembly includes a seat base and a seat back
and is capable of supporting a patient; at least one foot pad
attached near the first end of the base plate; a plurality of
non-retractable wheels attached near the second end of the base
plate; and a plurality of wheels attached near the first end of the
base plate, the first end wheels capable of being in a
weight-bearing position, in which the base plate is supported by
the first end wheels and the second end non-retractable wheels, or
being in a disengaged position, in which the base plate is
supported by the foot pad and the second end non-retractable
wheels, wherein a foot pedal actuates a lift system that switches
the first end wheels from the disengaged position to the
weight-bearing position such that the base plate has a ground
clearance of less than about one-half inch and the base plate can
be repositioned on a relatively flat surface.
3. The bottom support of claim 2 wherein the lift system includes a
mechanism for locking the first end wheels in the weight-bearing
position.
4. A piece of furniture for medical settings, comprising: a base
plate with a first end and a second end; a column attached to the
base plate and a seat assembly attached to the column, the seat
assembly being suitable for supporting a patient; a plurality of
non-retractable wheels attached to the second end of the base
plate, the non-retractable wheels extending below the base plate by
not more than about one-quarter inch; one or more feet attached to
the first end of the base plate, wherein the feet are capable of
leveling the base plate when the base plate is on a substantially
flat surface; a plurality of retractable wheels attached to the
first end of the base plate, wherein when the retractable wheels
are retracted the first end of the base plate rests on the feet and
when the retractable wheels are engaged the first end of the base
plate rests on the retractable wheels and the retractable wheels
can be switched between retracted and engaged positions via a lever
that actuates a lift mechanism; and the piece of furniture can be
repositioned in a room with a relatively flat floor when the
retractable wheels are engaged but does not include a handle for
pushing or steering above the base plate and does not include a
braking system that is accessible to a user above the base plate.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of and claims the benefit
of U.S. patent application Ser. No. 14/298,209 titled "Retractable
Wheel Base" and filed on Jun. 6, 2014.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] Not applicable.
BACKGROUND OF THE INVENTION
[0003] This invention relates to tables and chairs used in medical
settings. Medical examination and treatment tables and chairs tend
to be relatively heavy and thus can be difficult to move once in
place in an exam room or office. It is often necessary, however, to
clean around and under such tables and chairs, especially, for
example, after a biohazard spill. Many tables or chairs have
stationary bases, which are inexpensive but require special lifting
and/or moving equipment since they are generally too heavy to lift
or even slide manually. One approach for improving mobility has
been to include swiveling and locking caster wheels on each corner
of the base of the table or chair. However, such designs tend to be
expensive, and the larger bases required to accommodate caster
wheels on each corner of the base can create tripping hazards for
patients and medical care providers. Another option, as described
in published application EP 0366365 A2 entitled, "Improvements in
surgical and/or examination tables" by Spruill et al., is to
include four retractable caster wheels on the base of the table.
However, having all the caster wheels be retractable increases the
cost and complexity of the table.
[0004] Therefore, there is a need for medical examination tables
and chairs that can be safely and easily switched between
stationary and mobile states and that can be produced relatively
simply and inexpensively.
BRIEF SUMMARY OF THE INVENTION
[0005] It is an object of the present invention to provide an
examination, procedure, or surgical table or chair for use in the
medical, dental, or veterinary fields that can be quickly, safely
and easily switched between a stationary state and a mobile state
wherein the table or chair includes a base plate with fixed wheels
on one end and on the other end stationary foot pads and
retractable wheels that can be engaged by a lift mechanism that can
transfer the weight of the table or chair from the foot pads onto
the wheels.
[0006] It is a further object of the invention that the lift
mechanism for forcing the wheels downward and thereby lifting the
table or chair off the foot pads on one end of the medical
examination table or chair and onto the wheels on that end be a
mechanical, hydraulic, or electrical actuator.
[0007] It is a further object of the invention that a mechanical
lift mechanism have an over-center configuration such that the
wheels will be locked in the engaged position.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a side view of an examination table of the present
invention with rear caster wheels retracted.
[0009] FIG. 2 is a side view of an examination table of the present
invention with rear caster wheels engaged.
[0010] FIG. 3 is a perspective view of a base of the present
invention.
[0011] FIG. 4 is a side view of a lift mechanism with rear caster
wheels retracted.
[0012] FIG. 5 is a side view of a lift mechanism with rear caster
wheels engaged.
[0013] FIG. 6 is a perspective view of a lift mechanism of the
present invention when the caster wheels are retracted.
[0014] FIG. 7 is a perspective view of a lift mechanism of the
present invention when the caster wheels are engaged.
[0015] FIG. 8 is a perspective view of an embodiment of a base of
the present invention.
[0016] FIG. 9 is a side view of a base of an embodiment of a base
of the present invention.
[0017] FIG. 10 is a perspective view of another embodiment of a
base of the present invention.
[0018] FIG. 11 is an end view of another embodiment of a base of
the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0019] Referring to FIG. 1, a unit is shown that includes a medical
examination table on a column support on a base plate 21 in which
rear caster wheels 17 are retracted and not bearing the weight of
the base plate 21. With the rear caster wheels 17 retracted, the
unit is in a stationary state and the base plate 21 rests on foot
pads in the rear and wheels in the front. The foot pads may be any
suitable material, including hard rubber or plastic or may be an
extension of the base plate. In FIG. 1 the base plate 21 is shown
resting on two rear leveling feet 19 and two front wheels 20, which
can be any suitable wheels for a medical examination table or
chair, including swiveling caster wheels, for example. Preferably,
however, the front wheels 20 are low-profile fixed wheels, which
can be less expensive compared to swiveling caster wheels and can
have smaller profiles around the base plate 21 as well. This, in
combination with the retractable rear caster wheels, enables the
table to have a base footprint with a smaller size, which helps to
minimize the tripping hazard for patients and medical care
providers compared to a table having locked, swiveling,
non-retracting caster wheels on both ends, although such an
arrangement may be suitable in some circumstances. The rear caster
wheels 17 of the present invention also can reduce the cost of
production because the rear caster wheels 17 do not have to be
locking wheels since when the rear caster wheels 17 are retracted
the table settles onto stationary pads, such as the rear leveling
feet 19 as shown, which help prevent the table from moving
inadvertently while in the stationary position. To reduce the
chance of sideways motion while the unit is in the stationary
position, the front wheels 20 are preferably non-swiveling and
oriented to roll only forward or backward. Further, the rear
stationary feet are preferably leveling feet but can be any
suitable stationary foot pads. Preferably, the foot pad or pads are
of a size such that when the base plate 21 rests on the rear feet
and the front wheels, the base plate 21 will be approximately
level, or can be adjusted to be so with the use of leveling
feet.
[0020] Referring to FIG. 2, the unit is now shown in a mobile state
where the rear caster wheels 17 are engaged on the ground or floor
beneath the base plate 21. In this position, the unit can be
conveniently moved to another location in order to allow for
cleaning of spills, for example. When unit is in the mobile
position, the rear leveling feet 19 are off the ground and no
longer bearing the weight of base plate 21. The rear caster wheels
17 can be engaged, and disengaged, using any suitable switch
mechanism, such as a button, a hand lever, touch screen, or pedal
12. As shown, the pedal 12 is a foot pedal located near the rear of
the unit. A second pedal 12 could be included on the opposite side
of the unit for convenience, as can be seen in FIGS. 3, 6 and
7.
[0021] By raising only the half of the unit (the front half always
rests on the front wheels 20), the force required to put the unit
into a mobile mode with the rear caster wheels 17 engaged is
roughly half the amount of force that required if wheels in the
front had to be engaged as well. Because the units generally need
only be moved within a room, such as for cleaning purposes, when in
the mobile state, the clearance between the bottom of the base and
the floor can be quite limited, for example about one-quarter inch.
This allows the non-retractable wheels 20 to be inconspicuous and
further minimizes the distance the unit must be lifted in order to
engage the rear caster wheels 17.
[0022] While this design requires only half the table to be lifted
to engage the rear wheels, the forces required to engage the rear
caster wheels 17 may still be substantial. Therefore, a suitable
lift mechanism is provided to engage and retract the rear caster
wheels 17. The lift mechanism may be coupled between the base plate
21 and a caster arm 16, for example, to which the rear caster
wheels 17 can be attached. The lift mechanism can include a linkage
system that includes one or more actuators that can directly or
indirectly force the caster arm 16 downward a sufficient distance
and with sufficient force to place the rear caster wheels 17 onto
the ground or floor such that the weight of the unit transfers to
rear caster wheels 17 and off of leveling feet 19.
[0023] According to an exemplary embodiment, the lift mechanism may
be a mechanical linkage arrangement, as shown in FIGS. 3-7. The
mechanical advantage generated by this linkage arrangement allows a
typical user to easily engage and retract the rear caster wheels 17
by pressing on pedal 12 with his or her foot. The over-center
alignment of the linkage arrangement when the rear caster wheels 17
are engaged also provides a safety feature in that this
configuration allows the lift mechanism to be self-locking.
Additional weight applied to the table (such as if a person were to
lean or sit on the table) would not cause the linkage arrangement
to disengage and drop to the retracted position.
[0024] In the stationary state, the rear caster wheels 17 are
retracted and the base plate 21 is supported by the rear leveling
feet 19 and the front wheels 20. To move the unit, a user would
engage the rear caster wheels 17 by pressing down on a portion of
the pedal 12 (as shown in FIG. 3 the portion of pedal 12 to be
pressed downward to reach the engaged position is the rearward
portion of pedal 12). Referring now to FIGS. 3-7, which depict an
exemplary mechanical linkage lift mechanism, in a preferred
embodiment pressing down on the rearward portion of the pedal 12
causes a shaft 13 to rotate (counterclockwise as shown in FIGS. 3
and 4), which in turn cause cranks 14 to also rotate
(counterclockwise from the retracted position shown in FIGS. 4 and
6 to the engaged position shown FIGS. 5 and 7). The cranks 14 would
then force links 15 to shift toward an engaged position (a forward
movement as depicted), which would cause caster arm brackets 25 to
rotate about link-arm pivot pins 23 that connect the links 15 and
the caster arm brackets 25 (as can be seen from FIG. 4 to FIG. 5
and from FIG. 6 to FIG. 7). The resulting motion of the caster arm
brackets 25 thus forces caster arm 16, which is connected to the
caster arm brackets 25, downward. The rear caster wheels 17 are
attached to the bottom of the caster arm 16 and so the downward
motion of the caster arm 16 presses the rear caster wheels 17 into
the floor, thereby raising the base plate 21 off of the leveling
feet 19 and transitioning the weight of the unit onto the rear
caster wheels 17. In this position, the unit can be rolled to a new
location. Preferably, the rear caster wheels 17 are swiveling so
that the unit can be easily rolled in any direction even if the
front wheels 20 are non-swiveling.
[0025] Preferably the mechanical linkage lift mechanism includes an
over-center configuration so that no catch or locking mechanism is
needed to keep the rear caster wheels 17 in the engaged setting. As
can be seen in FIGS. 4 and 5, the linkage mechanism can maintain
the engaged setting through the alignment of the cranks 14 and the
links 15 in the engaged position, which can be such that crank-link
pivot pins 22 that link the cranks 14 and the links 15 will be just
slightly forward of a pivot axis (which in FIG. 5 can be visualized
as a vertical line between the end of the shaft 13 and the link-arm
pivot pin 23). The resulting over-center geometry creates a
self-locking mechanism in the engaged setting since the weight of
the unit will tend to provide a force that acts to prevent the
shaft 13, links 15 and cranks 14 from moving out of the engaged
position.
[0026] To disengage the rear caster wheels 17 using the mechanical
linkage lift mechanism and place the unit back into a stationary
mode, the user would press on an opposite portion of the pedal 12
(that is, opposite from the portion pressed to engaged the rear
caster wheels 17, which is a forward portion of the pedal 12 as
shown) while the pedal 12 is in the engaged position, as can be
seen in FIGS. 5 and 7, for example. Pressing on the opposite
portion of the pedal 12 while the pedal 12 is in the engaged
position causes the cranks 14 and links 15 to move away from the
over-center position and so the weight of the unit would then force
the links 15 toward the retracted position (a rearward motion as
shown from FIG. 5 to FIG. 4, for example), which would cause the
caster bracket arms 25 to pivot in a manner to pull caster arm 16
upward, resulting in the rear caster wheels 17 being lifted upwards
and allowing the base plate 21 to rest on the leveling feet 19 in a
stationary setting. Springs 18 could further retract the caster arm
16 so that the rear caster wheels 17 would lift fully off the
ground or floor (as shown for example in FIG. 4) when the unit is
in the stationary mode. In this manner, the present invention
allows medical examination tables and chairs to be compliant with
ADA low entry requirements in a stationary state and also to be
easily relocated when in the mobile state.
[0027] In addition, stops 24 could be built into the links 15 that
would engage the shaft 13 in order to provide limits to the motion
of the linkage assembly in both the retracted and engaged
positions, as can be seen in FIG. 4, in which the shaft 13 is
against stops 24 located on a forward portion of the links 15 when
the rear caster wheels 17 are in the retracted position and in FIG.
5, in which the shaft 13 is against stops 24 located on a rearward
portion of the links 15 when the rear caster wheels 17 are in the
engaged position.
[0028] Alternatively, the lift mechanism may be powered by an
electric actuator, for example by coupling an electric actuator to
a linkage lift mechanism so that the lift mechanism is electrically
powered and controlled. As depicted in FIGS. 8 and 9, for example,
which shows a base plate 210 with fixed wheel 200, an electric
actuator 126 is connected to a linkage mechanism in order to rotate
a shaft that results in a caster arm 116 being driven downward and
caster wheels 117 engaging the ground. To disengage the caster
wheels 117, the actuator 126 would cause the shaft to rotate in the
opposite direction, causing the caster arm 116 to raise and lift
the caster wheels 117 off the ground. The actuator 126 can be
anchored to base plate 210 via bracket 127 or any suitable
anchoring arrangement.
[0029] In addition, other suitable lift mechanisms could include
hydraulic actuators, pneumatic actuators, and electric actuators
that can be arranged to engage and retract the retractable wheels.
For example, as shown in FIGS. 10 and 11, an electric actuator 226
is coupled to base plate 310 using bracket 227 and may be
positioned such that when the actuator 226 is in the extended
position, the caster arm 216 is forced downward and caster wheels
217 are moved into the engaged position and bear the weight of base
plate 310 (along with fixed wheel 300). When the actuator 226 is in
the retracted position, the caster arm 216 will be raised, thus
raising the caster wheels 217 off the ground and returning the
weight of base plate 310 to foot pads. In this arrangement, the
actuator 226 may be a push-only actuator that relies on gravity to
move or return the actuator 226 to the retracted position. Other
configurations of actuator/wheels may be appropriate depending on
the type of table or chair.
[0030] The above description could apply to a unit that has other
equipment attached to the base plate instead of a medical
examination table, such as a medical chair, dental chair,
veterinary table, utility cart or other units or furniture for
which it would be desirable to toggle quickly, easily and safely
between mobile and stationary states. In addition, while the above
description refers to rear and front aspects of the units, such
distinctions are used for convenience of description and could be
reversed without deviating from the present invention.
* * * * *